When feeding envelopes from the bottom of a stack of the envelopes, a weight must be placed on top of the stack to enable driving of the last few envelopes of the stack. One prior arrangement has placed a weight on the top envelope of the stack but has not constrained it. Another prior arrangement used a weight conforming to the top envelope and moved in a vertical path. Still another prior arrangement moved a weight on an arc while maintaining the envelope engaging surface of the weight substantially parallel to the floor of the envelope feeder.
The weight assembly of the present invention is an improvement of the prior arrangements in that the weight is constrained while having its envelope engaging surface remain substantially parallel to the floor of the envelope feeder. By constraining the weight so that its envelope engaging surface is substantially parallel to the floor of the envelope feeder at any vertical position of the weight, the weight engages the uppermost envelope in the stack of envelopes at its highest point. Thus, if an envelope is curled or twisted so as to not be flat, the constrained weight provides more force on the highest point of the top envelope of the stack; this tends to push that point downwardly.
Since the curled or twisted portion of the envelope is at the highest point of the envelope to be fed, this curling or twisting of the envelope makes it more difficult to feed it into separating rollers, which are employed to feed only the lowermost envelope. However, by maintaining the constrained weight substantially parallel to the floor of the envelope feeder, particularly adjacent the separating rollers, this problem is significantly avoided.
An object of this invention is to provide an envelope feeder having a weight for engaging the top of a stack of envelopes in which the weight is maintained in a desired orientation at all times while the weight is freely movable along a controlled vertical path.
Another object of this invention is to provide an envelope feeder in which the height of the stack of envelopes is limited when the width of the envelopes exceeds a predetermined minimum.
Other objects of this invention will be readily perceived from the following description, claims, and drawings.